General

In this section you can adjust a variety of V-Ray parameters related to the overall operation of the renderer.

Parameters

Raycaster
parameters

Here
you can control various parameters of V-Ray's Binary Space Partitioning
(BSP) tree.

One of the basic operations that V-Ray must perform is raycasting - determining if a
given ray intersects any geometry in the scene, and if so - identifying
that geometry. The simplest way to implement this would be to test the
ray against every single render primitive (triangle) in the scene.
Obviously, in scenes with thousands or millions of triangles this is
going to be very slow. To speed this process, V-Ray organizes the scene
geometry into a special data structure, called a binary
space partitioning (BSP) tree.

The BSP tree is a hierarchical data structure, built by
subdividing the scene in two parts, then looking at each of those two
parts and subdividing them in turn, if necessary and so on. Those
"parts" are called nodes
of the tree. At the top of the hierarchy is the root
node - which represents the bounding box of the whole
scene; at the bottom of the hierarchy are the leaf
nodes - they contain references to actual triangles from
the scene.

Max tree depth
- the maximum depth of the tree. Larger values will cause V-Ray to take
more memory, but the rendering will be faster - up to some critical
point. Values beyond that critical point (which is different for every
scene) will start to slow things down. Smaller values for this
parameter will cause the BSP tree to take less memory, but rendering
will be slower.

Min leaf size
- the minimum size of a leaf node. Normally this is set to 0.0, which
means that V-Ray will subdivide the scene geometry regardless of the
scene size. By setting this to a different value, you can make V-Ray to
quit subdividing, if the size of a node is below a given value.

Face/level coef
- controls the maximum amount of triangles in a leaf node. If this
value is lower, rendering will be faster, but the BSP tree will take
more memory - up to some critical point (which is different for every
scene). Values below that critical point will make the rendering slower.

Default geometry
- internally V-Ray maintains four raycasting engines. All of them are
built around the idea of a BSP tree, but have different uses. The
engines can be grouped into raycasters for non-motion blurred and for
motion blurred geometry, as well as for static and dynamic geometry.
This parameter determines the type of geometry for standard 3ds Max
mesh objects. Note that some objects (displacement-mapped objects, VRayProxy and VRayFur objects, for
example) always generate dynamic geometry, regardless of this setting.

Static - all
geometry is precompiled into an acceleration structure at the beginning
of the rendering and remains there until the end of the frame. The
static raycasters are not limited in any way and will consume as much
memory as necessary.

Dynamic -
geometry is loaded and unloaded on the fly depending on which part of
the scene is being rendered. The total memory taken up by the dynamic
raycasters can be controlled by the Dynamic
memory limit parameter.

Auto - some
objects are compiled as static geometry, while others as dynamic. V-Ray
makes the decision on which type to use based on the face count for an
object and the number of its instances in the scene.

Dynamic memory limit
- the total RAM limit for the dynamic raycasters. Note that the memory
pool is shared between the different rendering threads. Therefore, if
geometry needs to be unloaded and loaded too often, the threads must
wait for each other and the rendering performance will suffer.

Render region
division

Here you can control various parameters of V-Ray's rendering
regions (buckets). The bucket is an essential part of the distributed
rendering system of V-Ray. A bucket is a rectangular part of the
currently rendered frame that is rendered independently from other
buckets. Buckets can be sent to idle LAN machines for processing and/or
can be distributed between several CPUs. Because a bucket can be
processed only by a single processor the division of the frame in too
small a number of buckets can prevent the optimal utilization of
computational resources (some CPUs stay idle all the time). However the
division of the frame in too many buckets can slow down the rendering
because there is a some time overhead related with each bucket (bucket
setup, LAN transfer, etc).

X -
determines the maximum region width in pixels (Region
W/H is selected) or the number of regions in the
horizontal direction (whenRegion
Count is selected)

Y -
determines the maximum region height in pixels (Region
W/H is selected) or the number of regions in the vertical
direction (whenRegion
Count is selected)

Region sequence
- determines the order in which the regions are rendered. Note that the
default Triangulation
sequence is best if you use a lof of dynamic
geometry (displacement-mapped objects, VRayProxy or VRayFur objects), since
it walks through the image in a very consistent manner so that geometry
that was generated for previous buckets can be used for the next
buckets. The other sequences tend to jump from one end of the image to
another which is not good with dynamic geometry.

Reverse sequence
- reverses the region sequence order.

Previous render
- this parameter determines what should be done with the
previous image in the virtual frame buffer when rendering starts. Note
that this parameter has no effect on the final result
of the rendering; it is implemented simply as a convenient way to
distinguish between parts from the current frame being rendered, and
part left over from the previous rendering. The
possible values are:

Unchanged -
no changes will be made - the virtual frame buffer remains the same;

Cross -
every second pixel of the image will be set to black;

Fields -
every other line of the image will be set to black;

Darken - the
colors in the image will be darkened.

Blue - the
previous image is tinted in blue.

Distributed
rendering

Distributed rendering
is the process of computing a single image over several different
machines. Note that this is different from distributing the frame over
several CPU's in a single machine, which is called multithreading. V-Ray supports
multithreading, as well as distributed rendering.

Before you can use the distributed rendering option, you
must determine the machines that will take part in the computations.
Both 3ds Max and V-Ray need to be properly installed on those machines,
although they don't need to be authorized. You must make sure that the
V-Ray spawner application is running on those machines - either as a
service, or as a stand-alone application. Refer to the Installation
section for more details on configuring and running the V-Ray
spawner.

Settings... -
this button opens the V-Ray distributed rendering settings
dialog. See the Distributed
rendering section for more information.

Frame stamp

The frame stamp is a convenient way to put some short text
over the rendered images. It can be useful in many ways - for example,
in network rendering, to quickly determine which frames were rendered
by which machine. The frame stamp is one line of text, which appears at
the bottom of the image.

Checkbox -
turns the frame stamp on and off.

Edit box -
here you enter the text you wish to appear in the images. You can also
use some special keywords, all of which begin with the percent symbol
(%). The keywords are replaced by V-Ray with the corresponding value:

Keyword

Meaning

%vrayversion

the current version of
V-Ray

%filename

the name of the current
scene file

%frame

the number of the current
frame

%primitives
*

the number of unique
intersectable primitives
generated for the current frame*

%rendertime

the render time for the
current frame

%computername

the network name of the
computer

%date

the current system date

%time

the current system time

%w

the width of the image in
pixels

%h

the height of the image
in pixels

%camera

the name of the camera for
this frame (if rendering
from a camera, empty string otherwise)

%"<maxscript
parameter
name>"

the value of any V-Ray
parameter, given its
MaxScript name (see section on MaxScript).
Note that you must enclose the parameter name in quotation marks (").
Also note that this option only works when rendering to the 3ds Max
frame buffer.

%ram

the amount of physical
memory (in KBytes) installed
on the system

%vmem

the amount of virtual
memory (in KBytes) available
on the system

%mhz

the clock speed of the
system CPU(s)

%os

the operating system

* An intersectable
primitive is a primitive that provides a direct method for intersection
with a ray (such as a triangle, the infinite plane generated by a VRayPlane plugin etc).
Most often, the number of these primitives is the same as the number of
triangles (faces) processed by V-Ray for the current frame. Note that
this may be different from the total number of triangles in the scene.
With the dynamic raycaster, only geometry that is actually needed is
generated and accounted for. Geometry that is not generated is not
included in this count.

Font - this
button allows you to choose a font and font attributes for the text in
the frame stamp.

Full width
- when this option is checked, the frame stamp will take the whole
width of the image, otherwise the stamp will be only as wide as the
text is.

Justify -
specifies the position of the stamp:

Left - the
stamp is placed on the left of the image.

Center - the
stamp is centered.

Right - the
stamp is placed on the right side of the image.

Object
Settings / Light Settings

Presets

V-Ray log

These parameters control the
V-Ray messages window. During rendering, V-Ray writes various
information in the file C:\VRayLog.txt. The messages window shows some
of that information so that you can view it without the need to
manually open that file.

Each message can fall into one of four categories, which are
colored in a different way in the messages window. Those catergories
are errors (colored in red), warnings (colored in green), informative
messages (colored in white) and debug messages (colored in black).

Show window
- when this is turned on, V-Ray will show the messages window at the
start of every render.

Level -
this determines what kind of messages will be showed in the window:

1 - only
error messages

2 - error
and warning messages

3 - errors,
warnings and informative messages

4 - all
messages

Log file -
this parameter determines the location and the name of the log file.
The default log file is C:\VRayLog.txt

Other parameters

MAX-compatible ShadeContext
- V-Ray carries all its computations in world space. However,
some 3ds Max plugins (notably atmospherics) take it as granted that the
renderer works in camera space, because this is what the default
scanline renderer does. To preserve compatibility with such plugins,
V-Ray emulates work in camera space by converting the various points
and vectors passed to and from other plugins. In addition to slowing
down V-Ray by forcing it to convert
values all the time, working in camera space messes up with camera
modifiers such as the Technical camera script. This why you have the
option of turning off the camera-space emulation.

Check for missing files
- when this is on, V-Ray will try to find any missing files in the
scene and will put up a dialog listing them, if there are any. The
missing files will also be printed to the C:\VRayLog.txt file. If this
option is on, and you render the scene with distributed rendering, and
if a render servers detects missing files, it will refuse to render the
scene.

Optimized atmospheric
evaluation - normally in 3ds Max, atmospherics are
avaluated after the surface behind them has been shaded. This may be
unnecessary if the atmospheric is very dense and opaque. Turning this
option on will cause V-Ray to first evaluate the atmospheric effects,
and shade the surface behind them only if the atmospherics are
sufficiently transparent.

Low thread priority
- turning this on will cause V-Ray to use threads of lower priority
when rendering.